This is a normal chemical reaction. At high temperature, a large amount of iron ions will be dissolved in the soup, which will be easily hydrolyzed to produce iron hydroxide precipitate, which will be decomposed into iron oxide and water. Iron oxide is black, so the soup will turn black. It is absolutely harmless to human body. Don't worry, have a good meal.

The practice of pettitoes soup

Ingredients: 2kg trotters, 50g peanuts, 6 ejiao jujube, refined salt 1 teaspoon, vinegar 1 teaspoon, cooking wine 1 teaspoon, spices 1 serving, and 3 slices of ginger.

1, cut pig's trotters into small pieces, boil them in cold water and beat them into foam.

2. Wash the cooked trotters with cold water.

3. Boil the water in the casserole, add cooking wine, bread and ginger, and pour the trotters.

4. Wash peanuts and red dates.

5. Pour peanuts and red dates into the pot.

6. Cover it and bring it to a boil. Simmer until soft and rotten, turn off the heat and season with salt.